This invention relates to compounds that contain vinyl silane and electron donor or electron acceptor functionality that can be used as adhesion promoters or curable compositions.
Adhesive composition s are used in the fabrication n an assembly of semiconductor packages and microelectronic devices, such as in the bonding of integrated circuit chips to lead frames or other substrates, and the bonding of circuit packages or assemblies to printed wire boards. Lead frames can be fabricated of 42Fe/58Ni alloy (Alloy 42), copper, or silver- or palladium-coated copper, and wire boards of ceramic or laminate, and adhesives that in general have good performance may be deficient when used on one or more of these substrates.
The addition of adhesion promoters to the adhesive compositions or the use of curable resins that contain adhesion promoting capability as the adhesive would serve to correct this deficiency.
This invention relates to compounds that contain both vinyl silane functionality and electron donor or electron acceptor functionality. In another embodiment, this invention is an adhesive, coating, or encapsulant composition containing the inventive compounds.
In one embodiment, this invention is a compound having the structure 
in which m and n independently are 0, 1, 2, or 3, but cannot both be 0, q is 1 or 2;
is 0, 1, or 2; X and Xxe2x80x2 independently are 
xe2x80x83R and R1 independently are an alkyl, cycloalkyl, or aromatic group; R2 is a vinyl, alkyl, cycloalkyl or aromatic group (which may be contained within a small molecular entity, oligomer or polymer); and E and Exe2x80x2 are independently an electron donor or electron acceptor.
Suitable electron acceptor groups are, for example, maleimides, acrylates, fumarates and maleates. Suitable electron donor groups are, for example, vinyl ethers, vinyl silanes, and carbon to carbon double bonds external to an aromatic ring and conjugated with the unsaturation in the aromatic ring, such as styrenic and cinnamyl groups.
In another embodiment, this invention is a curable composition, such as an adhesive, coating, or encapsulan, containing the inventive vinyl silane compounds. The composition can be in paste form prepared by milling or blending the components, or in film form, made by film making techniques known to those skilled in the art. The curable composition will include optionally a curing agent, and optionally a filler.
The vinyl silane compounds can be the main component in the curable composition or can be added as an adhesion promoter to another curable resin. When used as an adhesion promoter, the amount of the vinyl silane compound used in the curable composition will be an effective amount to promote adhesion and, in general, an effective amount will range from 0.005 to 20.0 percent by weight of the formulation,
Examples of curable resins for use as the main component other than the inventive vinyl silanes include epoxies, electron donor resins (for example, vinyl ethers, thiol-enes, and resins that contain carbon to carbon double bonds attached to an aromatic ring and conjugated with the unsaturation in the aromatic ring, such as compounds derived from cinnamyl and styrenic starting compounds), and electron acceptor resins (for example, fumarates, maleates, acrylates, and maleimides).
Suitable curing agents are thermal initiators and photoinitiators present in an effective amount to cure the composition. In general, those amounts will range from 0.5% to 30%, preferably 1% to 20%, by weight of the total organic material (that is, excluding any inorganic fillers) in the composition. Preferred thermal initiators include peroxides, such as butyl peroctoates and dicumyl peroxide, and azo compounds, such as 2,2xe2x80x2-azobis(2-methyl-propanenitrile) and 2,2xe2x80x2-azobis(2-methyl-butanenitrile). A preferred series of photoinitiators is one sold under the trademark Irgacure by Ciba Specialty Chemicals. In some formulations, both thermal initiation and photoinitiation may be desirable: the curing process can be started either by irradiation, followed by heat, or can be started by heat, followed by irradiation. In general, the curable compositions will cure within a temperature range of 70xc2x0 C. to 250xc2x0 C., and curing will be effected within a range of ten seconds to three hours. The actual cure profile will vary with the components and can be determined without undue experimentation by the practitioner.
The formulations may also comprise thermally or electrically conductive or nonconductive fillers, Suitable conductive fillers are carbon black, graphite, gold, silver, copper, platinum, palladium, nickel, aluminum, silicon carbide, boron nitride, diamond, and alumina. Suitable nonconductive fillers are particles of vermiculite, mica, wollastonite, calcium carbonate, titania, sand, glass, fused silica, fumed silica, barium sulfate, and halogenated ethylene polymers, such as tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride, vinylidene chloride, and vinyl chloride. If present, fillers generally will be in amounts of 20% to 90% by weight of the formulation.
The following are the Synthetic Procedures used to make the vinyl silane compounds disclosed in this specification, Examples of the vinyl silane compounds and performance in curable compositions.
PROCEDURE 1. Reaction of alcohol or amine with vinyl silane. One mole equivalent of alcohol or amine and triethylamine are mixed in dry toluene at 0xc2x0 C., to which is added one mole equivalent of vinyl silane dissolved in toluene. The mixture is allowed to react for four hours at room temperature, after which the solvent is evaporated to give the product.
PROCEDURE 2. Reaction of phenol or acetoacetate with alkyl or alkenyl halide. One mole equivalent of phenol or acetoacetate is charged to a three-necked flask equipped with a mechanical stirrer, condenser, and inlet/outlet tube for nitrogen. Methyl ethyl ketone is added and the reaction placed under nitrogen gas. Alkyl or alkenyl halide is added through a syringe and stirring initiated. Potassium carbonate is added and the reaction mixture heated at 50xc2x0 C. for 11 hours, allowed to cool to room temperature, and vacuum filtered. The filtrate is washed with 5% NaOH and 10% Na2SO4. The organic layer is dried over MgSO4, and the solvent evaporated off to give the product.
PROCEDURE 3. Reaction of isocyanate with amine. One mole equivalent of isocyanate is solvated in toluene in a three-necked flask equipped with a mechanical stirrer, addition funnel and nitrogen inlet/outlet. The reaction is placed under nitrogen and the solution heated to 60xc2x0 C. The addition funnel is charged with one mole equivalent of amine in toluene, and this solution is added to the isocyanate solution over ten minutes. The resulting mixture is heated for an additional three hours at 60xc2x0 C., after which it is allowed to cool to room temperature. The solvent is removed in vacuo to give the product.
PROCEDURE 4. Reaction of isocyanate with alcohol. One mole equivalent of isocyanate is solvated in toluene in a three-necked flask equipped with a mechanical stirrer, addition funnel and nitrogen inlet/outlet. The reaction is placed under nitrogen and catalytic of dibutyltin dilaurate is added with stirring as the solution is heated to 60xc2x0 C. The addition funnel is charged with one mole equivalent of alcohol dissolved in toluene. This solution is added to the isocyanate solution over ten minutes, and the resulting mixture is heated for an additional three hours at 60xc2x0 C. After the reaction is allowed to cool to room temperature, the solvent is removed in vacuo to give the product.
PROCEDURE 5. Reaction of alkyl halide with amine or mercaptan. One mole equivalent of alkyl halide is solvated in THF in a three neck flask equipped with a mechanical stirrer and addition funnel. The addition funnel is charged with one mole equivalent of amine or mercaptan in THF and this solution is added to the alkyl halide solution over ten minutes at 0xc2x0 C. The resulting mixture is stirred for 12 hours at room temperature, after which the solvent is removed in vacuo and ether and water are added to the resulting material. The organic layer is extracted and dried over MgSO4, and the solvent removed in vacuo to give the product.